[Short Stem, Straight Stem or Anatomical Stem: Free Decision or Recommendations?]

Area of Science:

• Orthopedic Surgery
• Biomedical Engineering

Background:

• Total hip arthroplasty (THA) aims to alleviate pain, but function, stability, and longevity are also critical.
• Hip stem designs have evolved significantly since Charnley's modern THA.
• This paper focuses on straight, anatomical, and short stem designs in THA.

Purpose of the Study:

• To evaluate recommendations for specific hip stem designs in total hip arthroplasty.
• To compare the biomechanical properties and clinical implications of different stem types.
• To inform surgeon choice based on patient-specific factors.

Main Methods:

• Review of existing literature on straight, anatomical, and short hip stems.
• Analysis of stem anchorage (metaphyseal vs. diaphyseal) and associated risks like stress shielding.
• Consideration of femoral morphology variations and patient-specific factors.

Main Results:

• Straight stems, the oldest type, carry a risk of stress shielding depending on diaphyseal anchorage.
• Anatomical stems aim for natural load-bearing but may have fitting limitations.
• Short stems are designed for anatomical stress distribution, reduced bone resection, and less thigh pain.

Conclusions:

• No single stem design is universally recommended; choice depends on biomechanical principles and patient-specific factors.
• Femoral morphology, including deformities and osteoporosis, influences stem selection.
• Optimal stem selection requires considering patient anatomy, biomechanics, and fixation methods.